I get about a dime size red then quench it then move about an inch or so away then do it again till I get the results I am looking for. I hammer and dolly the raised spots out and see if the oil can is gone.

To keep the shrinking disk from squeeling put some bar soap on it and keep a little water and soap in a spray bottle on the surface to keep things lubed. It will keep the disk from galling to the metal you are heating with it.

Ok, that sounds a bit more intense than I was working it, going to try your method and see if I can win. At this point I am almost afraid to hammer/dolly anymore for fear of stretching more.
Can a s disc make enough heat with soap on it?